Edges or faces might be crossing

[agon1]

Currently designing the Al Janoub stadium but cant figure out a way to fix the edges or faces that might be crossing. After making the shape i decided to weld all of the points in the end to create a pointy shape at the end of the geometry. Are there better ways to approach the modelling of this form? 

I attached my file and a screenshot of the problem. 

[glenn-chun · Accepted solution]

Using quads (See Case 3 below) is the best way to fix Error 2.